The present invention is particularly directed to a generally rectangular frame or support platform for a plurality of printed circuit boards. In particular the invention is directed to such a support arrangement which greatly facilitates the removal of one circuit board or card when two or more such cards are assembled in abutting relationship, so that even a card inside two adjacent circuit boards can be removed without necessitating the removal of either of the adjacent circuit boards.
Various electronic systems are assembled in modular form, with several sub-systems, the power supply, and input and output portions on a plurality of printed circuit boards, frequently termed "cards". In the electronic system arrangement technology, very often components are assembled on or in a rack arrangement which has a pair of vertical bars at the front. Sub-systems or components are then mounted to the two front bars, and often interconnected by relatively short connectors at the back or sides of the assembly. This is analogous to the mounting or stacking of a plurality of sub-systems for a home audio arrangement, such as a receiver, amplifier, tape deck, equalizer, and so forth. When lightweight materials such as printed circuit cards with miniaturized components thereon are assembled to the front of a rack, often the first or major sub-system is on the larger card, and it is assembled first by screws or other fasteners at the top of the support structure. The second card is then assembled just under the first, often by pushing it downwardly so that connectors can be mated to intercouple circuits on the two boards. The second card is then fastened by screws or similar fasteners after it is placed in abutting, electrically coupled contact with the first card.
A third card and other cards can then be added in the same manner, so that each is placed to abut the last-fastened card, and is then itself fixed in place by using screws which pass through the card edges and into correspondingly tapped apertures in the supporting bars.
The difficulty encountered with this system arrangement is that, if three cards are fixed in place in this way, and it is desired to remove the second card from between the first and third, the third card must first be entirely removed from the rack before the second can be removed. After changes or repairs are made to the second card, it can then be re-inserted, and the third card replaced in the original arrangement. However if it is only necessary to remove the second card, it is highly desirable that some method or arrangement be provided to allow this removal without necessitating the removal of an additional card or cards from the system.